JP7283327B2 - Wavelength conversion element, light source device and projector - Google Patents

Description

The present invention relates to a wavelength conversion element, a light source device and a projector.

A light source device has been proposed that irradiates a phosphor with excitation light emitted from a light source and uses the fluorescence emitted from the phosphor as illumination light. In Patent Document 1 below, fluorescence is generated by causing excitation light incident from the first surface of a light guide to enter a phosphor arranged on the second surface side opposite to the first surface of the light guide. However, a light source device is disclosed in which illumination light including excitation light and fluorescence is extracted from the end surface of the phosphor.

U.S. Pat. No. 9,921,353

However, in the above light source device, the illuminance distribution of the excitation light with which the phosphor is irradiated becomes non-uniform. In addition, when a specific region of the phosphor is locally irradiated with the excitation light, the phosphor generates heat, resulting in a decrease in fluorescence emission efficiency.

In order to solve the above problems, a wavelength conversion element of one aspect of the present invention includes a first wavelength conversion member that is excited by a first light and emits a second light having a wavelength band different from that of the first light; A bonded body in which a first light guide member that transmits the first light and the second light is bonded; a reflecting member that reflects at least one of the first light and the second light; , and a second surface of the first light guide member parallel to the first direction are joined to each other, and the first light beam crosses the first direction among the plurality of outer peripheral surfaces. It is characterized in that the light is incident on the joined body from the first outer peripheral surface where the light is incident.

The joined body has a second wavelength conversion member joined to a third surface opposite to the second surface of the first light guide member, and the first light guide member includes the first wavelength conversion member. It may be sandwiched between the member and the second wavelength conversion member.

The second wavelength conversion member may be configured to be excited by the first light and emit a third light having a wavelength band different from that of the first light and the second light.

The bonded body has a second light guide member that is bonded to a fourth surface opposite to the first surface of the first wavelength conversion member and transmits the first light and the second light, and The first wavelength conversion member may be sandwiched between the first light guide member and the second light guide member.

The first wavelength conversion member includes a first member that emits the second light when excited by the first light, and a wavelength band different from that of the first light and the second light when excited by the first light. and a second member that emits the third light having

A configuration further comprising a diffusing element that is arranged to face a second outer peripheral surface opposite to the first outer peripheral surface of the outer peripheral surface of the joined body and that diffuses at least one of the first light and the second light. good too.

The first light guide member may be made of sapphire.

A light source device according to one aspect of the present invention includes a light source that emits the first light and the wavelength conversion element according to the aspect described above.

A projector according to one aspect of the present invention includes the light source device according to the aspect described above, a light modulation device that modulates light from the light source device according to image information, and a projection optical device that projects the light modulated by the light modulation device. and.

1 is a diagram showing a schematic configuration of a projector according to a first embodiment; FIG. It is a figure which shows schematic structure of an illuminating device. FIG. 3 is a cross-sectional view of a wavelength conversion element; FIG. 5 is a cross-sectional view of a wavelength conversion element in the projector of the second embodiment; It is a sectional view of a wavelength conversion element of a third embodiment. It is a sectional view of a wavelength conversion element of a fourth embodiment. It is a sectional view of a wavelength conversion element of a fifth embodiment.

(First embodiment)
A first embodiment of the present invention will be described below with reference to FIGS. 1 to 3. FIG.
In the drawings below, in order to make each component easier to see, the scale of dimensions may be changed depending on the component.

An example of the projector according to this embodiment will be described.
FIG. 1 is a diagram showing a schematic configuration of a projector according to this embodiment.
As shown in FIG. 1, the projector 1 of this embodiment is a projection type image display device that displays a color image on a screen SCR. The projector 1 includes an illumination device 2 , a color separation optical system 3 , an optical modulator 4 R, an optical modulator 4 G, an optical modulator 4 B, a synthesizing optical system 5 , and a projection optical device 6 . The configuration of the illumination device 2 will be described later.

The color separation optical system 3 includes a first dichroic mirror 7a, a second dichroic mirror 7b, a reflecting mirror 8a, a reflecting mirror 8b, a reflecting mirror 8c, a relay lens 9a, and a relay lens 9b. . The color separation optical system 3 separates the illumination light WL emitted from the illumination device 2 into red light LR, green light LG, and blue light LB, guides the red light LR to the light modulation device 4R, and converts the green light LG into light. The light is guided to the modulator 4G, and the blue light LB is led to the light modulator 4B.

The field lens 10R is arranged between the color separation optical system 3 and the light modulation device 4R, substantially parallelizes the incident light, and emits it toward the light modulation device 4R. The field lens 10G is arranged between the color separation optical system 3 and the light modulation device 4G, substantially parallelizes the incident light, and emits it toward the light modulation device 4G. The field lens 10B is arranged between the color separation optical system 3 and the light modulation device 4B, and substantially parallelizes the incident light and emits it toward the light modulation device 4B.

The first dichroic mirror 7a transmits the red light component and reflects the green light component and the blue light component. The second dichroic mirror 7b reflects the green light component and transmits the blue light component. Reflecting mirror 8a reflects the red light component. Reflecting mirror 8b and reflecting mirror 8c reflect the blue light component.

The red light LR that has passed through the first dichroic mirror 7a is reflected by the reflecting mirror 8a, passes through the field lens 10R, and enters the image forming area of the light modulator 4R for red light. The green light LG reflected by the first dichroic mirror 7a is further reflected by the second dichroic mirror 7b, passes through the field lens 10G, and enters the image forming area of the light modulator 4G for green light. The blue light LB transmitted through the second dichroic mirror 7b passes through the relay lens 9a, the incident-side reflecting mirror 8b, the relay lens 9b, the exit-side reflecting mirror 8c, and the field lens 10B, and passes through the blue-light optical modulator 4B. incident on the image forming area.

Each of the light modulating device 4R, the light modulating device 4G, and the light modulating device 4B modulates incident color light according to image information to form image light. Each of the light modulating device 4R, the light modulating device 4G, and the light modulating device 4B is composed of a liquid crystal light valve. Although not shown, incident-side polarizing plates are arranged on the light incident sides of the optical modulator 4R, the optical modulator 4G, and the optical modulator 4B. Emission-side polarizing plates are arranged on the light exit sides of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B, respectively.

The synthesizing optical system 5 synthesizes the image lights emitted from the light modulators 4R, 4G, and 4B to form full-color image light. The synthesizing optical system 5 is composed of a cross dichroic prism having a substantially square shape in plan view, which is obtained by bonding four rectangular prisms. A dielectric multilayer film is formed on the substantially X-shaped interface where the rectangular prisms are bonded together.

The image light emitted from the synthesizing optical system 5 is enlarged and projected by the projection optical device 6 to form an image on the screen SCR. That is, the projection optical device 6 projects the light modulated by the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B. The projection optical device 6 is composed of a plurality of projection lenses.

An example of the illumination device 2 of this embodiment will be described.
FIG. 2 is a diagram showing a schematic configuration of the illumination device 2. As shown in FIG.
As shown in FIG. 2, the illumination device 2 includes a light source device 2A, an integrator optical system 31, a polarization conversion element 32, and a superimposing lens 33a. The integrator optical system 31 and the superimposing lens 33 a constitute a superimposing optical system 33 .

The light source device 2A includes an array light source (light source) 21A, a collimator optical system 22, an afocal optical system 23, a first retardation plate 28a, a polarization separating element 25, a first condensing optical system 26, A wavelength conversion element 40 , a second retardation plate 28 b , a second condensing optical system 29 , and a diffuse reflection element 30 are provided.

An array light source 21A, a collimator optical system 22, an afocal optical system 23, a first retardation plate 28a, a polarization splitting element 25, a second retardation plate 28b, a second condensing optical system 29, The diffuse reflection elements 30 are arranged in order on the optical axis ax1. The wavelength conversion element 40, the first condensing optical system 26, the polarization separation element 25, the integrator optical system 31, the polarization conversion element 32, and the superimposing lens 33a are arranged in order on the illumination optical axis ax2. ing. The optical axis ax1 and the illumination optical axis ax2 are in the same plane and orthogonal to each other.

The array light source 21A includes a plurality of semiconductor lasers 21 as solid-state light sources. A plurality of semiconductor lasers 21 are arranged in an array in a plane perpendicular to the optical axis ax1. The semiconductor laser 21 emits a blue light beam BL in a first wavelength band, specifically a laser beam in the first wavelength band with a peak wavelength of 460 nm, for example. The array light source 21A emits a light beam consisting of a plurality of light beams BL. The array light source 21A of this embodiment corresponds to the "light source" in the claims.

A light beam BL emitted from the array light source 21 A enters the collimator optical system 22 . The collimator optical system 22 converts the light beam BL emitted from the array light source 21A into parallel light. The collimator optical system 22 is composed of a plurality of collimator lenses 22a arranged in an array. Each of the multiple collimator lenses 22 a is arranged corresponding to each of the multiple semiconductor lasers 21 .

The light beam BL that has passed through the collimator optical system 22 enters the afocal optical system 23 .
The afocal optical system 23 adjusts the thickness (diameter) of the bundle of rays BL. The afocal optical system 23 is composed of, for example, a convex lens 23a and a concave lens 23b.

The light beam BL that has passed through the afocal optical system 23 is incident on the first retardation plate 28a. The first retardation plate 28a is, for example, a rotatable half-wave plate. The light beam BL emitted from the semiconductor laser 21 is linearly polarized light. By appropriately setting the rotation angle of the first retardation plate 28a, the light beam BL passing through the first retardation plate 28a is a light beam containing the S-polarized component and the P-polarized component with respect to the polarization separation element 25 at a predetermined ratio. can be By rotating the first retardation plate 28a, the ratio between the S-polarized component and the P-polarized component can be changed.

The light beam BL containing the S-polarized component and the P-polarized component generated by passing through the first retardation plate 28 a enters the polarization separation element 25 . The polarization separation element 25 is composed of, for example, a polarization beam splitter having wavelength selectivity. The polarization separation element 25 forms an angle of 45° with respect to the optical axis ax1 and the illumination optical axis ax2.

The polarization splitting element 25 has a polarization splitting function of splitting the light beam BL into a light beam BLs of the S-polarization component and a light beam BLp of the P-polarization component for the polarization splitting element 25 . Specifically, the polarization separation element 25 reflects the S-polarized light beam BLs and transmits the P-polarized light beam BLp. In addition to the polarization splitting function, the polarization splitting element 25 has a color splitting function of transmitting a yellow light component having a wavelength band different from that of the blue light beam BL regardless of the polarization state.

The S-polarized light beam BLs emitted from the polarization separating element 25 is incident on the first condensing optical system 26 . The first condensing optical system 26 condenses the light beam BLs as excitation light toward the wavelength conversion element 40 . The first condensing optical system 26 is composed of a first lens 26a and a second lens 26b. The first lens 26a and the second lens 26b are composed of convex lenses. The light beam BLs emitted from the first condensing optical system 26 enters the wavelength conversion element 40 in a condensed state.

In this embodiment, the wavelength conversion element 40 converts incident excitation light (light beams BLs) into fluorescence YL in a second wavelength band different from the first wavelength band of the excitation light. The wavelength conversion element 40 of this embodiment is composed of a fixed type wavelength conversion element that is not rotatable by a motor or the like.
The configuration of the wavelength conversion element 40 will be described later.

The yellow fluorescence YL generated by the wavelength conversion element 40 is collimated by the first condensing optical system 26 and then enters the polarization separation element 25 . As described above, the polarization separation element 25 has the property of transmitting the yellow light component regardless of the polarization state, so the fluorescence YL is transmitted through the polarization separation element 25 .

On the other hand, the P-polarized light beam BLp emitted from the polarization separation element 25 is incident on the second retardation plate 28b. The second retardation plate 28b is composed of a quarter-wave plate arranged in the optical path between the polarization separation element 25 and the diffuse reflection element 30. As shown in FIG. Therefore, the P-polarized light beam BLp emitted from the polarization separation element 25 is converted into, for example, clockwise circularly polarized blue light BLc1 by the second retardation plate 28b, and then enters the second light collecting optical system 29. do.

The second condensing optical system 29 is composed of a first lens 29a and a second lens 29b. The first lens 29a and the second lens 29b are composed of convex lenses. The second condensing optical system 29 causes the blue light BLc1 to enter the diffuse reflection element 30 in a condensed state.

The diffuse reflection element 30 is arranged on the optical path of the light beam BLp emitted from the polarization separation element 25 and diffusely reflects the blue light BLc1 emitted from the second condensing optical system 29 toward the polarization separation element 25 . It is desirable that the diffuse reflection element 30 performs Lambertian reflection of the blue light BLc1 and does not disturb the polarization state of the blue light BLc1.

The light diffusely reflected by the diffuse reflection element 30 is hereinafter referred to as blue light BLc2. In the present embodiment, blue light BLc2 with a substantially uniform illuminance distribution is obtained by diffuse reflection of blue light BLc1. For example, the clockwise circularly polarized blue light BLc1 is diffusely reflected by the diffuse reflection element 30 to become the counterclockwise circularly polarized blue light BLc2.

The blue light BLc2 is converted into parallel light by the second condensing optical system 29, and then re-enters the second retardation plate 28b. The counterclockwise circularly polarized blue light BLc2 is converted into S-polarized blue light BLs1 by the second retardation plate 28b. The S-polarized blue light BLs1 is reflected toward the integrator optical system 31 by the polarization separation element 25 .

Thereby, the blue light BLs1 is combined with the fluorescence YL that has passed through the polarization separation element 25, and is used as the illumination light WL. That is, the blue light BLs1 and the fluorescence YL are emitted in the same direction from the polarization separation element 25, and the blue light BLs1 and the fluorescence (yellow light) YL are combined to generate white illumination light WL.

The illumination light WL is emitted toward the integrator optical system 31 . The integrator optical system 31 is composed of a first lens array 31a and a second lens array 31b.
Each of the first lens array 31a and the second lens array 31b has a configuration in which a plurality of lenses are arranged in an array.

The illumination light WL transmitted through the integrator optical system 31 enters the polarization conversion element 32 . The polarization conversion element 32 has a polarization separation film and a retardation plate. The polarization conversion element 32 converts the illumination light WL containing the unpolarized fluorescence YL into linearly polarized light to be incident on the light modulators 4R, 4G, and 4B.

The illumination light WL transmitted through the polarization conversion element 32 enters the superimposing lens 33a. The superimposing lens 33a cooperates with the integrator optical system 31 to homogenize the illuminance distribution of the illumination light WL in the illuminated area. Thus, the illumination device 2 generates illumination light WL.

The configuration of the wavelength conversion element 40 will be described below.
FIG. 3 is a cross-sectional view of the wavelength conversion element 40. As shown in FIG. 3 and subsequent drawings, the light beam BLs that is incident on the phosphor layer 43 to generate the fluorescence YL may be referred to as the excitation light E in some cases.
As shown in FIG. 3, the wavelength conversion element 40 includes a bonded body 41 and a reflecting member 42. As shown in FIG. The joined body 41 is configured by joining a phosphor layer (first wavelength conversion member) 43 and a light guide member (first light guide member) 44 . The wavelength conversion element 40 of this embodiment is a reflective wavelength conversion element that emits the fluorescence YL from the surface on which the excitation light E is incident.

The joint 41 is composed of a hexahedron. The joint 41 has six outer peripheral surfaces. Specifically, the joined body 41 includes a first outer peripheral surface 41a, a second outer peripheral surface 41b, a third outer peripheral surface 41c, a fourth outer peripheral surface 41d, a fifth outer peripheral surface 41e, a sixth outer peripheral surface 41f, have.

In this embodiment, the joined body 41 has a rectangular shape when viewed from the normal direction of the first outer peripheral surface 41a. The first outer peripheral surface 41a is the entrance surface of the excitation light E and the exit surface of the fluorescence YL in the wavelength conversion element 40 . The second outer peripheral surface 41b is a surface facing the first outer peripheral surface 41a. That is, the first outer peripheral surface 41a and the second outer peripheral surface 41b face opposite sides. In the present embodiment, the second outer peripheral surface 41b is a surface that constitutes the bottom of the joined body 41. As shown in FIG. The third outer peripheral surface 41 c intersects the first outer peripheral surface 41 a and is parallel to the first direction D<b>1 in which the excitation light E is incident on the wavelength conversion element 40 . Here, the first direction D1 is a direction along the top and bottom in FIG.

The fourth outer peripheral surface 41d is a surface facing the third outer peripheral surface 41c. That is, the fourth outer peripheral surface 41d and the third outer peripheral surface 41c face opposite sides. The fifth outer peripheral surface 41e and the sixth outer peripheral surface 41f face opposite sides. In this embodiment, the fifth outer peripheral surface 41e is the outer surface of the joined body 41 on the front side in the penetrating direction of the paper surface of FIG. .

The phosphor layer 43 has a first joint surface (first surface) 43a parallel to the first direction D1, a surface 43b facing away from the first joint surface 43a, an upper surface 43c, a lower surface 43d, and a front surface 43e. , and a rear side 43f.

An upper surface 43 c of the phosphor layer 43 is a surface that intersects the first direction D<b>1 and forms part of the first outer peripheral surface 41 a of the joined body 41 . A lower surface 43 d of the phosphor layer 43 is a surface that intersects the first direction D 1 and forms part of the second outer peripheral surface 41 b of the joined body 41 . A surface 43 b of the phosphor layer 43 constitutes a third outer peripheral surface 41 c of the joined body 41 . The front side surface 43e of the phosphor layer 43 constitutes a part of the outer surface of the bonding body 41 on the front side in the through-the-paper direction of FIG. forming part of the outer surface of the side.

The phosphor layer 43 contains a phosphor material that converts the excitation light (first light) E emitted from the array light source 21A into fluorescence (second light) YL having a wavelength band different from that of the excitation light E. The second wavelength band is, for example, 490-750 nm, and the fluorescence YL is yellow light containing green and red light components. Note that the phosphor layer 43 may contain a single-crystal phosphor.

The phosphor layer 43 contains, for example, an yttrium-aluminum-garnet (YAG)-based phosphor. Taking YAG:Ce containing cerium (Ce) as an activator as an example, the phosphor layer 43 is formed by mixing and solidifying raw material powders containing constituent elements such as Y ₂ O ₃ , Al ₂ O ₃ and CeO ₃ . Phase-reacted materials, Y-Al-O amorphous particles obtained by wet methods such as coprecipitation and sol-gel methods, YAG particles obtained by vapor phase methods such as spray drying, flame pyrolysis, and thermal plasma methods, etc. can be used.

The light guide member 44 is a member that transmits the excitation light E and the fluorescence YL.
The light guide member 44 has a second joint surface (second surface) 44a parallel to the first direction D1, a surface 44b facing away from the second joint surface 44a, an upper surface 44c, a lower surface 44d, and a front side surface 44e. , and a rear side 44f.

An upper surface 44 c of the light guide member 44 is a surface intersecting the first direction D<b>1 and constitutes a part of the first outer peripheral surface 41 a of the joined body 41 . A lower surface 44 d of the light guide member 44 is a surface that intersects the first direction D<b>1 and constitutes a part of the second outer peripheral surface 41 b of the joined body 41 . A surface 44 b of the light guide member 44 constitutes a fourth outer peripheral surface 41 d of the joined body 41 . The front side surface 44e constitutes a part of the outer surface of the joined body 41 on the front side in the through-paper direction of FIG.

In addition, although the constituent material of the light guide member 44 is not particularly limited, it is desirable to use a material having a refractive index close to that of the phosphor layer 43 and a high thermal conductivity. Sapphire, for example, can be used as a constituent material of the light guide member 44 .

The bonded body 41 of the present embodiment is configured by bonding a first bonded surface 43a of the phosphor layer 43 and a second bonded surface 44a of the light guide member 44 to each other. An adhesive (not shown) is provided between the first joint surface 43 a of the phosphor layer 43 and the second joint surface 44 a of the light guide member 44 . As the adhesive, it is preferable to use a material having a small refractive index difference with respect to the phosphor layer 43 and the light guide member 44 .

In the present embodiment, the reflecting member 42 faces the third outer peripheral surface 41c and the fourth outer peripheral surface 41d, which are surfaces parallel to the first direction D1, among the plurality of outer peripheral surfaces 41a to 41f of the joined body 41. are placed.

The reflecting member 42 reflects the excitation light E and fluorescence YL . As a constituent material of the reflecting member 42, a metal material having a high light reflectance such as aluminum or silver may be used, or a dielectric multilayer film may be used.

The reflecting member 42 is desirably arranged apart from the outer peripheral surface of the joined body 41 . That is, between the second outer peripheral surface 41b of the bonded body 41 and the reflecting member 42, between the third outer peripheral surface 41c of the bonded body 41 and the reflecting member 42, and between the fourth outer peripheral surface 41d of the bonded body 41 and the reflecting member 42 It is desirable that an air layer 45 is interposed between them.

The wavelength conversion element 40 is arranged so that the first outer peripheral surface 41 a of the joined body 41 faces the second lens 26 b of the first condensing optical system 26 . As a result, the excitation light E emitted from the first condensing optical system 26 enters the joined body 41 via the first outer peripheral surface 41a.

Next, the action and effect of the wavelength conversion element 40 of this embodiment will be described.
In the wavelength conversion element 40, the excitation light E condensed by the first condensing optical system 26 enters the joined body 41 from the first outer peripheral surface 41a. Specifically, the excitation light E enters the light guide member 44 along the first direction D1 from the upper surface 44c.

In the wavelength conversion element 40 of this embodiment, the propagation direction (first direction D1) in which the excitation light E propagates in the light guide member 44 is parallel to the joint interface between the light guide member 44 and the phosphor layer 43 . Therefore, the excitation light E incident on the light guide member 44 travels in the first direction D1 in the light guide member 44 and is guided toward the lower surface 44d side, and passes through the first bonding surface 43a to the phosphor layer 43. to produce fluorescence YL. At this time, since the excitation light E propagates in the light guide member 44 along the joint interface between the light guide member 44 and the phosphor layer 43, the excitation light E is directed toward the phosphor layer 43 (first joint surface 43a). uniformly illuminated. Therefore, the irradiation density of the excitation light E to the phosphor layer 43 can be kept low.

Therefore, according to the wavelength conversion element 40 of the present embodiment, by suppressing the irradiation density of the excitation light E to the phosphor layer 43, local heat generation in the phosphor layer 43 is suppressed, and the temperature rise of the phosphor layer 43 is suppressed. It is possible to suppress the decrease in fluorescence emission efficiency associated with.

Further, since the phosphor layer 43 is joined to the light guide member 44 on the incident surface of the excitation light E, the heat generated by the phosphor layer 43 due to the incidence of the excitation light E is efficiently dissipated through the light guide member 44. be done. Further, in the present embodiment, since sapphire having high thermal conductivity is used as the light guide member 44, the temperature rise of the phosphor layer 43 is suppressed by efficiently dissipating heat from the phosphor layer 43, thereby achieving high fluorescence conversion efficiency. realizable.

In the wavelength conversion element 40 of this embodiment, the fluorescence YL generated in the phosphor layer 43 is emitted into the light guide member 44, propagates through the light guide member 44, and is emitted from the upper surface 44c of the light guide member 44. . A part of the fluorescence YL is also emitted from the upper surface 43 c of the phosphor layer 43 . That is, the fluorescence YL emitted from the first outer peripheral surface 41a of the joined body 41 is composed of a fluorescent component emitted from the upper surface 44c of the light guide member 44 and a fluorescent component emitted from the upper surface 43c of the phosphor layer 43. be done.

Also, part of the light (excitation light E and fluorescence YL) propagating through the light guide member 44 reaches the surface 44 b of the light guide member 44 . Of the light that has reached the surface 44b of the light guide member 44, the light that has entered the surface 44b at an incident angle equal to or greater than the critical angle is totally reflected by the surface 44b and returned into the light guide member 44, where it enters the light guide member 44 again. propagates

On the other hand, light incident on the surface 44b at an incident angle less than the critical angle passes through the surface 44b and is emitted to the outside of the light guide member 44. FIG. In the wavelength conversion element 40 of the present embodiment, since the reflecting member 42 is provided so as to face the surface 44b of the light guide member 44, the light that has passed through the surface 44b is reflected by the reflecting member 42 and again reflected by the light guide member 44. Propagate inside.

Also, part of the light (excitation light E and fluorescence YL) propagating through the light guide member 44 reaches the lower surface 44 d of the light guide member 44 . The light reaching the lower surface 44d of the light guide member 44 is totally reflected by the lower surface 44d, or even if it passes through the lower surface 44d, it is reflected by the reflecting member 42 provided so as to face the lower surface 44d and enters the light guide member 44. It is returned and propagates through the light guide member 44 again.

Also, part of the fluorescence YL generated by the phosphor layer 43 or part of the excitation light E not converted into fluorescence YL by the phosphor layer 43 reaches the surface 43 b of the phosphor layer 43 . Of the fluorescence YL or the excitation light E reaching the surface 43b, the light incident on the surface 43b at an incident angle equal to or greater than the critical angle is totally reflected by the surface 43b and returned into the phosphor layer 43, and the excitation light E becomes the fluorescence YL , and the fluorescence YL is transmitted through the phosphor layer 43 and taken into the light guide member 44 .

Further, the fluorescence YL or the excitation light E incident on the surface 43b at an incident angle less than the critical angle passes through the surface 43b and is emitted to the outside of the bonded body 41. The excitation light E is used to generate fluorescence YL, and the fluorescence YL passes through the phosphor layer 43 and is taken into the light guide member 44. be Alternatively, the fluorescence YL reflected by the reflecting member 42 is emitted from the gap between the reflecting member 42 and the surface 43 b of the phosphor layer 43 .

As described above, in the wavelength conversion element 40 of the present embodiment, the excitation light E propagates through the light guide member 44 along the joint interface of the joined body 41 in which the light guide member 44 and the phosphor layer 43 are joined. Therefore, the uniformity of the illuminance distribution of the excitation light E can be improved by suppressing the optical density of the excitation light E in the phosphor layer 43 (first joint surface 43a). As a result, local heat generation in the phosphor layer 43 is suppressed, and a decrease in fluorescence emission efficiency due to temperature rise of the phosphor layer 43 can be suppressed. Therefore, fluorescent light YL is efficiently generated in the phosphor layer 43, so bright illumination light WL can be generated.

As described above, according to the wavelength conversion element 40 of the present embodiment, the illuminance distribution of the excitation light E in the phosphor layer 43 is made uniform and the temperature rise of the phosphor layer 43 is suppressed. Thereby, the wavelength conversion element 40 with high luminous efficiency can be realized. That is, according to the wavelength conversion element 40 of the present embodiment, it is possible to obtain the wavelength conversion element 40 with high heat dissipation and high wavelength conversion efficiency.

Further, since the light source device 2A of the present embodiment includes the wavelength conversion element 40 described above, it is possible to improve the luminous efficiency. Moreover, since the projector 1 of the present embodiment includes the light source device 2A, it can project a bright image.

(Second embodiment)
A second embodiment of the present invention will be described below with reference to FIG.
The configurations of the projector and the illumination device of the second embodiment are the same as those of the first embodiment, and the configuration of the wavelength conversion element is different from that of the first embodiment. Therefore, the overall description of the projector and lighting device is omitted.

FIG. 4 is a cross-sectional view of the wavelength conversion element 140 of this embodiment.
As shown in FIG. 4 , the wavelength conversion element 140 includes a bonded body 141 and a reflecting member 42 . The joined body 141 of the present embodiment is configured by joining a first phosphor layer (first wavelength conversion member) 143, a second phosphor layer (second wavelength conversion member) 144, and a light guide member 44. be done.

The first phosphor layer 143 and the second phosphor layer 144 have the same configuration as the phosphor layer 43 of the first embodiment. The first phosphor layer 143 includes a first bonding surface (first surface) 143a parallel to the first direction D1 and a surface 143b facing away from the first bonding surface 143a. The second phosphor layer 144 includes a first bonding surface 144a parallel to the first direction D1 and a surface 144b facing away from the first bonding surface 144a.

In this embodiment, the reflecting member 42 is arranged to face the third outer peripheral surface 141c and the fourth outer peripheral surface 141d parallel to the first direction D1 among the plurality of outer peripheral surfaces 141a to 141f of the joined body 141. .

In the joined body 141 of the present embodiment, the first joining surface 143a of the first phosphor layer 143 and the second joining surface 44a of the light guide member 44 are joined together, and the first joining surface 144a of the second phosphor layer 144 is joined. and the back surface (third surface) 44b opposite to the second joint surface 44a of the light guide member 44 are joined to each other.

That is, the light guide member 44 of this embodiment is sandwiched between the first phosphor layer 143 and the second phosphor layer 144 . In this embodiment, the surface 143b of the first phosphor layer 143 forms the third outer peripheral surface 141c of the joined body 141, and the surface 144b of the second phosphor layer 144 forms the fourth outer peripheral surface 141d of the joined body 141. .

Since the wavelength conversion element 140 of the present embodiment includes the joined body 141 in which the light guide member 44 is sandwiched between the first phosphor layer 143 and the second phosphor layer 144, excitation propagating in the light guide member 44 is Light E is incident on the first phosphor layer 143 and the second phosphor layer 144 to generate fluorescence YL, whereby bright fluorescence YL can be obtained.

(Third embodiment)
A third embodiment of the present invention will be described below with reference to FIG.
FIG. 5 is a cross-sectional view of the wavelength conversion element of this embodiment.
As shown in FIG. 5 , the wavelength conversion element 70 of this embodiment includes a bonded body 71 and a reflecting member 42 . The joined body 71 of this embodiment is configured by joining the phosphor layer 43 , the first light guide member 72 , and the second light guide member 73 .

The first light guide member 72 and the second light guide member 73 have the same configuration as the light guide member 44 of the first embodiment. The first light guide member 72 includes a second joint surface (second surface) 72a parallel to the first direction D1 and a surface 72b facing away from the second joint surface 72a. The second light guide member 73 includes a second joint surface 73a parallel to the first direction D1 and a surface 73b facing away from the second joint surface 73a.

In the present embodiment, the reflecting member 42 is arranged to face the third outer peripheral surface 71c and the fourth outer peripheral surface 71d, which are parallel to the first direction D1, among the plurality of outer peripheral surfaces of the joined body 71 .

In the bonded body 71 of the present embodiment, the first bonding surface 43a of the phosphor layer 43 and the second bonding surface 72a of the first light guide member 72 are bonded to each other, and the first bonding surface 43a of the phosphor layer 43 is opposite to the bonding surface 43a of the first light guide member 72. and the second joint surface 73a of the second light guide member 73 are joined to each other.

That is, the phosphor layer 43 of this embodiment is sandwiched between the first light guide member 72 and the second light guide member 73 . In this embodiment, the surface 72b of the first light guide member 72 constitutes the fourth outer peripheral surface 71d of the joined body 71, and the surface 73b of the second light guide member 73 constitutes the third outer peripheral surface 71c of the joined body 71. .

Since the wavelength conversion element 70 of the present embodiment includes the joined body 71 configured by sandwiching the phosphor layer 43 between the first light guide member 72 and the second light guide member 73, the excitation light E is transmitted through the first guide member. By propagating through the optical member 72 and the second light guide member 73, the light can be efficiently incident on both surfaces (the first bonding surface 43a and the front surface 43b) of the phosphor layer 43. FIG. Thereby, bright fluorescence YL can be generated in the phosphor layer 43 .

(Fourth embodiment)
A fourth embodiment of the present invention will be described below with reference to FIG.
FIG. 6 is a cross-sectional view of the wavelength conversion element of this embodiment.
As shown in FIG. 6, the wavelength conversion element 80 of this embodiment includes a bonded body 41, a reflecting member 42, and a diffusing element . The diffusion element 82 is arranged to face the second outer peripheral surface 41b of the outer peripheral surface of the joined body 41 opposite to the first outer peripheral surface 41a. The diffusion element 82 is bonded to the second outer peripheral surface 41b. Note that the diffusion element 82 may be arranged with a gap provided between it and the second outer peripheral surface 41b.

The diffusing element 82 is an element that diffuses light propagating through the light guide member 44 . The diffusion element 82 of this embodiment is a phosphor layer 82a. The phosphor layer 82 a has the same configuration as the phosphor layer 43 . As the phosphor layer 82a, a phosphor material having a high pore content rate or a phosphor having a surface with fine irregularities may be used to enhance light diffusion.

In the wavelength conversion element 80 of the present embodiment, since the phosphor layer 82a as the diffusing element 82 is provided on the second outer peripheral surface 41b of the joined body 41, the light propagates through the light guide member 44 to the second outer peripheral face of the joined body 41. The excitation light E reaching 41b can be converted into fluorescence YL by the phosphor layer 82a. This makes it possible to generate brighter fluorescence YL. Further, the phosphor layer 82a also functions as a diffusion element that diffusely reflects part of the excitation light E. FIG. The excitation light E is diffusely reflected in various directions by the phosphor layer 82a to enter the phosphor layer 43 and is used to generate fluorescence YL.
As described above, according to the wavelength conversion element 80 of the present embodiment, brighter fluorescence YL can be generated than the wavelength conversion element 40 of the first embodiment.

Note that the diffusing element 82 may be composed of a diffusing plate. In this case, the excitation light E incident on the third outer peripheral surface 41 c of the joined body 41 can be diffused and reflected in various directions, thereby making it easier to enter the phosphor layer 43 .

(Fifth embodiment)
A fifth embodiment of the present invention will be described below with reference to FIG.
FIG. 7 is a cross-sectional view of the wavelength conversion element of this embodiment.
As shown in FIG. 7, the wavelength conversion element 90 of this embodiment includes a bonded body 141, a reflecting member 42, and a diffusing element . The diffusion element 82 is arranged to face the second outer peripheral surface 141b of the outer peripheral surface of the joined body 141 opposite to the first outer peripheral surface 141a. The diffusion element 82 is bonded to the second outer peripheral surface 141b. Note that the diffusion element 82 may be arranged with a gap provided between it and the second outer peripheral surface 141b.

The diffusion element 82 diffusely reflects the light propagating through the light guide member 44 . The diffusion element 82 of this embodiment is a phosphor layer 82a.
In the wavelength conversion element 90 of the present embodiment, since the phosphor layer 82a as a diffusion element is provided on the second outer peripheral surface 141b of the joined body 141, the excitation light E propagating in the light guide member 44 enters the phosphor layer 82a. By doing so, brighter fluorescence YL can be generated. Further, the phosphor layer 82a also functions as a diffusion element that diffusely reflects part of the excitation light E. FIG. The excitation light E is diffused and reflected in various directions by the phosphor layer 82a, is incident on the first phosphor layer 143 or the second phosphor layer 144, and is used to generate fluorescence YL.
The wavelength conversion element 90 of the present embodiment can generate fluorescence YL that is brighter than the wavelength conversion element 140 of the second embodiment.

The diffusion element 82 may be composed of a diffusion plate. In this case, the diffusing element 82 diffuses the excitation light E and reflects it in various directions, thereby making it easier to enter the first phosphor layer 143 or the second phosphor layer 144 .

Although one aspect of the present invention has been described in the above embodiment, the content of the present invention is not limited to the above, and can be changed as appropriate without departing from the gist of the invention.
For example, in the above embodiment, the reflecting member 42 is arranged to face the second outer peripheral surface 41b, the third outer peripheral surface 41c, and the fourth outer peripheral surface 41d. You may make it arrange|position the reflecting member 42 to 41 f of 6th outer peripheral surfaces. According to this configuration, the light utilization efficiency can be improved by returning the light emitted from the joined body 41 to the outside into the joined body 41 . Also in the second embodiment, the reflecting member 42 may be arranged on the fifth outer peripheral surface 141e and the sixth outer peripheral surface 141f parallel to the first direction D1.

In the above embodiments, the wavelength conversion elements 40, 70, 80, 90, and 140 are reflective wavelength conversion elements. It can also be applied to a transmissive wavelength conversion element that emits light.

Further, in the second embodiment or the fifth embodiment, the first phosphor layer 143 and the second phosphor layer 144 may be composed of phosphors having different characteristics. For example, the first phosphor layer 143 emits green fluorescence (second light) by blue excitation light (first light), and the second phosphor layer 144 emits excitation light and fluorescence by blue excitation light (first light). Desired spectral characteristics can also be obtained by using a phosphor that emits yellow fluorescence or red fluorescence (third light) having a wavelength band different from that of green fluorescence.

Further, in the first embodiment, the third embodiment, or the fourth embodiment, the phosphor layer 43 may be configured by laminating two phosphors having different characteristics. For example, the phosphor layer 43 includes a first fluorescent member (first member) that emits green fluorescence (second light) by blue excitation light (first light) and a first fluorescent member (first member) that is excited by blue excitation light (first light). A second fluorescent member (second member) that emits yellow fluorescent light or red fluorescent light (third light) having a wavelength band different from light and green fluorescent light may be laminated.

DESCRIPTION OF SYMBOLS 1... Projector 2A... Light source device 4B, 4G, 4R... Light modulation device 6... Projection optical device 21A... Array light source (light source) 40, 70, 80, 90, 140... Wavelength conversion element 41, 71 , 141... Joined body 41a, 141a... First outer peripheral surface 41b, 71b, 141b... Second outer peripheral surface 42... Reflective member 43... Phosphor layer (first wavelength conversion member) 44... Light guide member ( First light guide member) 73 Second light guide member 82 Diffusion element 143 First phosphor layer (first wavelength conversion member) 144 Second phosphor layer (second wavelength conversion member) D1: first direction, E: excitation light (first light), YL: fluorescence (second light).

Claims (10)

a first wavelength conversion member that is excited by the first light and emits a second light having a wavelength band different from that of the first light; a first light guide member that transmits the first light and the second light; a conjugate to which is joined;
a reflecting member arranged to face at least one surface parallel to the first direction among the plurality of outer peripheral surfaces of the joined body, and reflecting at least one of the first light and the second light;
The joined body is configured by joining a first surface parallel to the first direction of the first wavelength conversion member and a second surface parallel to the first direction of the first light guide member to each other. and
the first light is incident on the joined body from a first outer peripheral surface intersecting the first direction among the plurality of outer peripheral surfaces ;
The reflecting member is also provided facing a second outer peripheral surface facing the first outer peripheral surface of the joined body on which the first light is incident,
The second light is emitted from the first wavelength conversion member and the first light guide member that constitute the first outer peripheral surface of the joined body.
A wavelength conversion element characterized by: The joined body has a second wavelength conversion member joined to a third surface opposite to the second surface of the first light guide member,
The wavelength conversion element according to claim 1, wherein the first light guide member is sandwiched between the first wavelength conversion member and the second wavelength conversion member. The reflecting member is provided so as to face the outer peripheral surface of the first wavelength conversion member and the outer peripheral surface of the second wavelength conversion member among the plurality of outer peripheral surfaces of the joined body.
3. The wavelength conversion element according to claim 2, characterized by: 3. The wavelength conversion according to claim 2, wherein the second wavelength conversion member is excited by the first light and emits third light having a wavelength band different from that of the first light and the second light. element. The joined body has a second light guide member that is joined to a fourth surface opposite to the first surface of the first wavelength conversion member and transmits the first light and the second light,
The wavelength conversion element according to claim 1, wherein the first wavelength conversion member is sandwiched between the first light guide member and the second light guide member. The first wavelength conversion member includes a first member that emits the second light when excited by the first light, and a wavelength band different from that of the first light and the second light when excited by the first light. The wavelength conversion element according to any one of claims 1 to 5 , further comprising: a second member that emits a third light having arranged to face a second outer peripheral surface opposite to the first outer peripheral surface of the outer peripheral surface of the joined body,
The wavelength conversion element according to any one of claims 1 to 6 , further comprising a diffusion element that diffuses at least one of the first light and the second light. The wavelength conversion element according to any one of claims 1 to 7 , wherein the first light guide member is sapphire. a light source that emits the first light;
A light source device comprising: the wavelength conversion element according to any one of claims 1 to 8 . a light source device according to claim 9 ;
a light modulating device that modulates light from the light source device according to image information;
a projection optical device that projects the light modulated by the light modulation device;
A projector comprising:

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